Magnetron



Feb, 25, H93 w. E. KOHLE ET'AL 2@31778 MAGNETRDN Filed Aug. 20, 1935 WILHELM EBERHARD KUHLE DIETRICH PRINZ FELIX HERRIGER INVENTORS Patented Feb. 25, 1936 UNITED STATES MAGNETRON Wilhelm Eberhard Khle, Dietrich Prinz, anti Felix Herriger, Berlin, Germany, assignors to Telefunken Gesellschaft fr Drahtlose Telegraphie m. b. H., Berlin, Germany, a corporation of Germany Applieation August 20, 1935, Serial N0. 36,940 In Germany July 5, 1934 3 Claims.

The invention relates to an electron discharge device for use at high frequeneles of the magnetron type, particularly to improvements in the magnetic circuit for such devices.

The conventional magnetron tube has an evacuated envelope containing a thermionic cathode und one or more anodes surrounding the cathocle. A magnetic field substantially parallel to the cathode is generated b-y an electroor permanent magnet. In order to efficiently utilize the magnetic flux to advantage lt is necessary 1:0 limit the air gap to small values.

It ls the principal object of our invention to provide an improved type of magnetron in which the magnetic field is usecl to its fullest advantage.

In accordance with the invention, the iron core cf the magnet is utilized to supply the heating current. A magnetron in which the cathode lilament is supported between two opposed leads sealed in opposite ends of the envelope is utilized. so that the filament lead-ins terminate in contact pieces received within recesses in the pole pieces of the magnet. The current carrying connections to the filament are provided by the pole pleces. Since the axial length of the envelope need not be greater than that of the electrode system proper, the magnetic airgap can be reduced to practically a minimum.

The novel features which we believe 1:0 be charaeterlstic of our invention are sei. forth with particularity in the appendecl claims, but the invention itself will best be understood by reference to the following description taken in connection with the accompanying drawing in which the figure in the drawlng is a schematic diagram partially in section of a magnetron embodylng our lnvention.

In the drawing the magnetron is provlded wlth an elongated. envelope I containing a thermionic cathode 2 and twosemi-cylindrical anode segments 3 and 4 providecl with leads l and. 8. The straight filament cathocle is supported between and terminates in two contacts 5 and 6. The magnetic field is generated by an electro-magnet having a U-shaped core 9 conductively divlded in the center so far as carrylng an electrle current ls concerned by means of a thin insulating disc I0, for example fibre. Obviously, the division of the yoke of the magnet by means of an alr gap is likewise sufficient, if the structural connection oi the two arms or legs is carried out by means of electrically insulating parts. The two arms of the iron core support the windlng II which can be connected to a direct voltage source at the terminals I2 and I3. Terminals I4 and I5 can be connectecl to a heating voltage source for supplying the cathode filament. In view of the large iron cross sectlon, no appreclable lass of heating voltage occurs. Obvlously, in plaee of an eleetro-mag-net, a permanent magnet could be used.

While we have indicated the preferred embodlment of our invention of which we are new aware and have also indicated only one specific application for which our invention may be employed, it will be apparent that our lnvention ls by no means limited to the exact forms illustrated er the use indicated, but that many variatlons may be made in the particular structure used. and. the purpose for which it is employed wlthout departing from the scope of our invention as Set forth in the appended claims.

What we claim as new is 1. An electron discharge device comprlsing an elongated evacuated envelope containing a straight thermionic cathode extending thru opposite ends of said envelope and an anode, magnetic poles positioned close to the ends of said envelope to provide a magnetic field parallel to said eathode, said poles being electrically insulated from each other and connected to opposlte ends cf the thermionic cathode serve as cur- 25 rent leads for said cathode.

2. A magnetron comprising an elongated evacuated envelope contaihing a straight thermionic cathode extending thru opposite ends of said envelope and a plurality of anodes, contacts on the outside of said envelope connected to said cathode, and. a U-shaped. discontinuous magnet formed to receive the envelope between its legs recessed for receiving said contacts, the legs constituting conductors for the heating current for said filament.

3. A magnetron having an elongated envelope provided with flat ends transverse to the longitudinal axis of the envelope, a straight thermionic cathode extending thru opposite ends of said envelope and provided with contacts at its ends anodes within said envelope positioned around said thermionie cathode, a U-shaped magnet for provicling a magnetic field parallel to said cathode and. having oppositely disposed pole faces on the legs of said magnet, said envelope being received. between said oppositely disposed pole faces, said faces having recesses for receiving the cathode contacts whereby the envelope is positioned close to the pole faces of said magnet, an insulator electrically insulating the opposite legs of said magnet and. terminals on said opposlte legs whereby a voltage can be applied to opposite ends of the thermionic cathode thru said lees.

WILHELM EBERHARD KUHLE. DIETRICH PRINZ. FELIX HERRIGER. 

